微博字数控制 老师通过下
<!DOCTYPE html>
<html>
<head>
<title>微博输入</title>
<script type="text/javascript" src="jquery-3.3.1.min.js"></script>
<style type="text/css">
body{font-size: 12px}
.box{width: 600px;height: 160px;border: 10px solid pink;margin: 0px auto;padding: 10px;}
img{float: left;}
.box1{float:left;margin-left: 255px;width: 150px;height: 24px;text-align: right;font-size:14px;color: #888 }
.box1 span{font-size: 16px;font-weight: bold;}
#text{width: 600px;height:100px;border: 1px solid #ccc;margin-top: 5px;}
.box #sp1,#sp2,#sp3,#sp4,#sp5,#sp6{float: left;width: 30px;height: 32px;line-height: 32px;padding-left: 26px;}
#sp1{background: url(images/an5.png) no-repeat left center}
#sp2{background: url(images/an5.png) no-repeat left center}
#sp3{background: url(images/an5.png) no-repeat left center}
#sp4{background: url(images/an5.png) no-repeat left center}
#sp5{background: url(images/an5.png) no-repeat left center}
#sp6{margin-left: 160px;margin-right: 15px;color:#888;}
#bt{float: left;width: 80px;height: 30px;border: none;background: #ffc09f;color: #fff;}
</style>
<script type="text/javascript">
var text,number,m,bt;
window.onload=function(){
text=document.getElementById('text');
number=document.getElementById('number');
bt=document.getElementById('bt');
text.onkeyup=function aa() {
m=140-text.value.length;
if (m<0) {
number.style.color="red"
} else {
number.style.color="#888"
}
number.innerHTML=m;
}
bt.onclick=function () {
if (m==140) {
alert('你还没有输入')
} else if(m<0){
alert('超过字数')
}
else{
alert('发布成功')
}
// body...
}
}
</script>
</head>
<body>
<div class="box">
<img src="images/12.png">
<div class="box1">还可以输入<span id="number"></span>字</div>
<textarea id="text"></textarea>
<span id="sp1">表情</span>
<span id="sp2">图片</span>
<span id="sp3">视频</span>
<span id="sp4">话题</span>
<span id="sp5">长微博</span>
<span id="sp6">公开</span>
<input type="button" value="发布" id="bt">
</div>
<script type="text/javascript">
var text,number,m
</script>
</body>
</html>